MAIDUGURI, Nigeria — Three militaries, using ground troops and warplanes, fought Boko Haram on at least two fronts Wednesday with hundreds of the Islamic fighters reported dead as the conflict took on a growing international perspective.

Chad’s army said its troops were attacked Tuesday in Cameroon by Boko Haram, the Nigerian extremist group that has slaughtered and kidnapped civilians and has had the upper hand against Nigeria’s military. The Chadian troops’ response underscores other African nation’s newfound resoluteness to combat what they perceive as a regional threat.

“Our valiant forces responded vigorously, a chase was immediately instituted all the way to their base at Gamboru and Ngala (in Nigeria), where they were completely wiped out,” spokesman Col. Azem Bermendoa said on national television Tuesday night.

More than 200 extremists and nine Chadian troops were killed, he said.

On Wednesday, hundreds of Boko Haram fighters driven out of Gamboru crossed the border and attacked Chadian military posts in Fotokol, in far northern Cameroon, residents and military officers said.

Cameroonian troops mobilized to join the Chadians in confronting the invaders, resident journalist Ledoux Blaise Mal Moussa told The Associated Press by telephone. The ongoing battle was confirmed by Cameroonian military officers who spoke on condition of anonymity because they are not authorized to speak to reporters. Most Fotokol residents had weeks ago fled the town.

Meanwhile, warplanes from Nigeria and jet fighters and helicopter gunships from Chad pursued a bombing campaign that has forced the Islamic fighters from more than a dozen towns in northeast Nigeria where Boko Haram declared an Islamic caliphate in August.